This study evaluated the hypothesis that in HIV-infected pregnant women receiving oral ZDV, HIVIG administered monthly beginning at 20-30 weeks gestation in combination with intravenous ZDV intrapartum, together with a single newborn dose of HIVIG within 12 hours after birth in combination with six weeks of newborn oral ZDV, reduces vertical HIV transmission compared with IVIG administered identically as a control agent. The primary objectives of this study were to evaluate the effect of combination therapy with HIVIG and ZDV, compared to IVIG and ZDV on the incidence of HIV infection in infants born to HIV-infected women. This study was closed to enrollment on 3/25/97 as the unexpectedly low overall transmission rate of 4.8% was well below the figures on which the initial power and sample size calculations were based. The data not only confirm the efficacy of ZDV for reduction of perinatal transmission, but extend this efficacy to women with more advanced disease and prior ZDV use.